1. Field of the Invention
The present invention relates to flip chips with solder pre-plated leadframes, and more particularly, to a flip chip with a solder pre-plated leadframe that includes locating holes for alignment.
2. Description of the Prior Art
The trend of miniaturizing packaging of semiconductor devices is driving the need to package a larger die in smaller packages. Current gold wire bond design rules limit die size to approximately 50% to 65% of the smallest dimension of the body size. Extra space is required to create a die attach area, space between the die attach area and wire bondable leads. The space prevents shorting between the die attach area and the leads. In addition, it provides some flexibility to loop the gold wire and form a reliable connection between the bond area and the bondable leads.
Methods have been developed for placing the flipped chip or xe2x80x9cdiexe2x80x9d directly on the leadframe wherein the leadframe includes leads directly coupled to the die attach pad, thus eliminating the need for the gold wire. The chip connection to the frame is done with solder paste that is placed on the die attach pad prior to chip attachment to the frame. The solder paste is intended to hold the chip in place after the chip is attached to the frame. The eutectic solder paste will also make connection between high lead bumps on the chip to the frame. However, there are problems with this technology in handling the leadframe and the die thereon prior to reflowing the solder paste and placing the mold around the leadframe. The process window at the holding station must be controlled in order to avoid any shifting of the die. The process control and mold compound variations sometimes create a shifted die which results in opens and shorts, which thus result in a rejection of the final semiconductor. This is detrimental to the overall manufacturing yield.
The present invention provides a semiconductor device that includes a leadframe having a plurality of leads. The leadframe includes at least two alignment holes. The semiconductor device further includes a die coupled to the leadframe with solder. The alignment holes help ensure that the die remains properly positioned on the leadframe prior to the solder reflow that attaches the die to the leadframe.
In accordance with one aspect of the present invention, the leads include down set areas for receiving solder balls for coupling the die thereto.
In accordance with another aspect of the present invention, the down set is 4 mils.
The present invention also provides a method for manufacturing a semiconductor device. The method includes providing a wafer, placing solder bumps on the wafer and dicing the wafer. The resulting die is then attached to a plurality of leads that are coupled together. The die attach takes place at a heating station in order to reflow the solder bumps to solder pre-plated leads. Additionally, at least two of the leads include locating holes for receiving solder bumps and thereby properly positioning the die. Plastic molding is placed around the resulting die and coupled leads and the leads are then trimmed and formed and separated from one another.